PEDT-02 Clinical usage of NCC Oncopanel/FoundationOne CDx for pediatric/AYA patients with recurrent malignant brain tumors

Backgrounds: Analyses of somatic mutations in malignant brain tumors have been used to make effective treatment strategies. NCC Oncopanel and FoundationOne CDx are custom targeted next-generation sequencing (NGS) panels. The cost for this analysis is 560,000 yen covered by National Health Insurance in Japan since June 2019. These methods can be applied for the solid cancers with no established therapies and relapsed after the standard therapies. Following these inclusion criteria, most malignant brain tumors, especially recurrent malignant brain tumors in pediatric/AYA generations, can be included. Object: To report the results of our initial experiences. Methods: In the last one year, we utilized these NGS panels for five patients with recurrent malignant brain tumors in this generations: 2 epithelioid glioblastomas; 1 anaplastic meningioma; 1 diffuse astrocytoma (gliomatosis cerebri); 1 atypical choroid plexus papilloma. Results: Final recommended treatments are as follows: BRAF/MEK inhibitors, bevacizumab, or anti-PD-1 antibody for one epithelioid glioblastoma; MEK inhibitor for another epithelioid glioblastoma previously treated by BRAF inhibitor and bevacizumab; ERK1/2 inhibitors for anaplastic meningioma. The diffuse astrocytoma had IDHR132H mutation. There was no clinical trial using IDH inhibitor for recurrent diffuse astrocytoma; thus, the final recommendation for this case was rechallenge of temozolomide. To date, only one NGS for a choroid plexus papilloma has been reported (Arch Pathol Lab Med, 2017). Our case had multiple actionable gene alterations, including TERT mutation and amplification of various genes. Unfortunately, there was no druggable gene alteration among them. Conclusions: Insurance-covered cancer gene panel tests could represent effective treatment options for some malignant brain tumors in pediatric/AYA generations. If the relapse is local and can be treated by repeat resections, we think the surgery is the first-line choice. But, in another situation, information from NGS panels should be obtained positively. Efforts to increase the utility of off-label use of drugs are encouraged.